1. Field of the Invention
The present invention relates generally to a vehicular height control system for an automotive suspension system. More specifically, the invention relates to an automotive height control system which is designed for performing vehicular attitude control for suppressing attitude change of a vehicular body and height regulating control for maintaining a vehicular height within a predetermined height range. Further particularly, the invention relates to an automotive height control system which is provided improved response characteristics in height adjustment in response to vehicular body displacement out of the target height range.
2. Description of the Background Art
Conventional automotive height control systems are provided pneumatic chambers variable of pneumatic pressure for adjusting pneumatic spring force for maintaining the vehicular height at a predetermined height range. Among such vehicular height control systems, some systems are associated with variable damping force suspension systems which are variable of suspension characteristics for absorbing road shock and for suppressing vehicular attitude change.
In such conventional vehicular height control systems, height adjustment tends to be disabled in response to attitude change since attitude change may cause temporary vehicular height variation to make it impossible to obtain precise vehicular height data. It is normal suspension procedure to give higher priority for attitude change suppressing operation than height regulating operation so that height adjustment is performed after vehicular attitude is stabilized. This clearly degrade response characteristics of height regulating operation in response to vehicular height variation due to change of load, such as upon getting in of the passenger or passengers, or upon getting out of the passenger or passengers since stability of the vehicular attitude has to be confirmed in advance of performing height regulating operation.